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Collection, Preservation and Display of Old Lawn Mowers

Atco 14 light - gear assembly

I recently took off the chain and gear assembly on the side of my acto light 14 1947. The problem is now after reassembly the chain keeps coming off when I engage the clutch. Upon inspection there appears to be quite a lot of play in the drive cog (the one between the other two) and it twists. 

can someone please help? I don't think I lost any bit when reassembling. Does anyone have a diagram or can advise how this can be tightened up as apart from the split pin head on the end there is no way to tighten up this part of the assembly.

thank you,



wristpin Sat, 11/04/2020

Put a steel rule or strait edge across the intermediate sprocket ( not cog, please) and see if it is in line with the front one. If it’s not in line one of them is probably incorrectly assembled  - such as a spacer in the wrong position.

Atco Andy Sat, 11/04/2020

Thanks wristpin,

here's a photo, how do I fix the spacing?



wristpin Sat, 11/04/2020

Im not familiar with that machine but I would expect the shaft that the sprocket runs on to be secured inside the chassis side plate by a large nut as it is on later Atcos. The shaft may even move on an eccentric or in a slot to assist with finding the correct tension between both the cylinder and the rear roller. Unless a bush has fallen out of the sprocket , the fact that it  appears to be flopping about suggests that said nut is loose. On latter machines that nut can be a bit of a pain to get at and somewhere in the less used section of my tool box is an open ended spanner bent to make the job easier.

Atco Andy Mon, 13/04/2020

There is a bush inside the sprocket and a nut head on the inside of the chassis plate as you suggest. I don't remember ever loosening this nut and having managed to get a spanner to it (it is a fiddle I get to) it's as tight as, it's going nowhere, I don't think it's been adjusted in the past 73 years!

could it be something else?

thanks again

villiers98 Sat, 16/05/2020

The angle of the intermediate sprocket is definitely wrong and there should be no play between the sprocket and the spindle it runs on. This will throw the chain off for certain. Try taking the intermediate sprocket off again and examine the spindle and sprocket. Could you plese  post more  photos of the 2 parts  if you ve not sorted it.

wristpin Sat, 16/05/2020

Take the sprocket off it’s shaft. Measure the diameter of the shaft, then measure the diameter of the hole in the  sprocket  . If there’s a big difference get down on hands and knees to pray that you find the bush that escaped when you dismantled it! It always amazes me just how far escapees can travel.

villiers98 Wed, 23/06/2021

I gather it's still not working well.  1 ) the primary chain tensioner ( clutch shaft to cutter sprocket chain ) should be acting on the front run of chain not back. Always on the slack side of the chain when in use.

2) Can you remove the split pin, collar and intermediate sprocket and take more photos . Either the bush in the sprocket is worn/missing , or the chain pulling  has bent the side plate . In this case put a piece of pipe over the spindle and gently bend it straight

Hope this helps